Visual function in children with Joubert syndrome

Aim: To describe visual function in children with Joubert syndrome and to investigate its possible association with diagnostic and developmental aspects. Method: This retrospective cross-sectional work included 59 patients (33 male; mean age 9 years 2 months, standard deviation 6 years 3 months, range 4 months to 23 years) diagnosed with Joubert syndrome from January 2002 to December 2020. Data about clinical (neurological, neuro-ophthalmological, developmental/cognitive) and diagnostic (e.g. genetic testing, neuroimaging, systemic involvement) evaluations were collected in a data set during a review of medical records. Clinical and diagnostic variables were described in terms of raw counts and percentages. A χ2 test was conducted to investigate their association with neuropsychological skills. Results: Ocular motor apraxia was highly represented in our cohort (75%), with a high prevalence of refractive defects and retinal abnormalities. Developmental delay/intellectual disability was frequent (in 69.5% of the sample), associated with retinal dystrophy (p = 0.047) and reduced visual acuity both for near (p = 0.014) and for far distances (p = 0.017). Interpretation: On the basis of the relevance of oculomotor and perceptual alterations and their impact on overall and cognitive impairment, we encourage early and multidisciplinary assessment and follow-up of visual function in children with Joubert syndrome. This would help in planning a personalized rehabilitation to sustain functional vision. Further studies will be important to explore the link between biological aspects and global functioning in children with Joubert syndrome. What this paper adds: Perceptual deficits and oculomotor impairments frequently coexist in Joubert syndrome. Retinal dysfunction may be present despite the absence of funduscopic abnormalities. Both perceptual and oculomotor impairments negatively affect cognitive development in Joubert syndrome.